1. Field of the Invention.
The present invention relates to electric motors generally and, more particularly, but not by way of limitation, to a novel electric motor which provides both linear and rotary motion at a single output shaft.
2. Background Art.
In certain applications, it is desirable to have a shaft which may selectively rotate and/or reciprocate. Such an application, for example, is in the robotic picking and placing of components where it may be required to axially move a component to an insertion position and then rotate the component to screw it in place. Conventional motor arrangements are often complicated and heavy, a substantial disadvantage for robotics applications. Another type of application requiring a shaft which may selectively rotate and/or reciprocate is in the precise control of laparoscopic and other such medical instruments.
In either type of application, it is frequently required that the linear motion be locked while rotary motion takes place. For a rotary/linear motor, this makes it desirable that the linear and rotary motions be controllable independently of one another.
A problem with motors having linear motion is that the motors frequently provide inadequate output shaft support when heavy side loads are imposed on the output shafts thereof.
Accordingly, it is a principal object of the present invention to provide an electric motor which provides both linear and rotary motion at a single output shaft.
It is an additional object of the invention to provide such an electric motor in which linear and rotary motions are controllable independently of one another.
It is another object of the invention to provide such an electric motor in which linear motion can be locked while rotary motion is provided.
It is a further object of the invention to provide such a motor that is simple and economical to manufacture.
An additional object of the invention is to provide such a motor that is lightweight and compact.
Another object of the invention is to provide a linear-type motor that has sufficient structure to support heavy side loads on the output shafts thereof.
Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.
The present invention achieves the above objects, among others, by providing, in a preferred embodiment, a linear/rotary motor, comprising: a housing; an output shaft extending from said housing; a rotary motor disposed within said housing, said output shaft being given rotational motion by said rotary motor; a linear motor disposed within said housing; a linear shaft axially moveable by said linear motor; and coupling means to join said linear shaft and said output shaft to permit transfer of axial motion from said linear shaft to said output shaft but to isolate rotational motion of said output shaft from said linear shaft.